Use two spaces for indentation consistently. Signed-off-by: Robin Jarry <robin@jarry.cc>
Ensure that install works on all platforms.
This commit drops Arch Linux in favor of a BSD so there's more variety in CI. Link: https://lists.sr.ht/~rjarry/aerc-devel/%3C20220122033806.91728-1-ktprograms%40gmail.com%3E